SERIES A-08700
MODEL A-08740
Univ
er
sal Opacity
Univer
ersal
Monitor
FEATURES
• Modbus communications.
• 4-20 mA DC output signal.
• Calibrated adjustment of alarm trip point
and time delay.
• Percent opacity calibration with
autocalibration mode.
• Easy to align, easy to install.
• Commercially available long-life lamp.
• DEP approved; UL and CUL pending.
APPLICATION
The Hays Cleveland Model A-08740 Universal Opacity
Monitor provides reliable, continuous measurement of the
density of confined particulates such as dust or smoke. It is
easy to calibrate and requires no routine maintenance other
than occasionally cleaning the sight glass.
The basic system consists of an electronics unit and two
breeching components. A light source directs a beam through
the measured particulate, and a light sensor receives the beam,
detects changes in opacity, and sends a proportional signal to
the electronics unit. The wide-beam light source and narrowview receiver make installation easy: alignment of the
breeching units does not need to be precise. The electronics
produces a digital readout of percent opacity and a 4-20 mA
DC output signal suitable for recording, display, or indication.
SPDT contacts are also provided for remote alarm or control
functions. A contact closure is provided for a remote alarm
(which can be purchased separately: Hays Cleveland L05500-00). The operator can select manual or automatic alarm
reset. Modbus communications for interface with a SCADA
system (Supervisory Control and Data Acquisition system) or
other controls is standard. A standard serial printer port is
provided. The electronics unit is available in open-mount,
surface-mount, and flush-mount formats. It can be installed in
any dry, convenient area within 250 feet of the light source and
receiver units. The standard model has a vacuum fluorescent
display with three status LED’s. There are four LED indicators
on units equipped with auxiliary functions (described below).
The Burner Cutoff Auxiliary Function is a delayed deenergization timer that shuts the burner down if an alarm
condition (opacity exceeding 20%) persists for 120 seconds.
The timer can be manually reset only after reduction of
opacity: it cannot be reset when opacity is above 20%. (This
feature meets the requirements of the New York City air
pollution control code for alarm and burner control functions). Model A-08740 Opacity Monitors equipped with the
Bulletin A08740.00
MODEL
A- 08740 OPACITY MONITOR
ELECTRONICS
burner cutoff function have four LED indicators on the front of
the electronics panel, marked Clear, Smoke, Alarm, and
Burner Off. In addition, an audible alarm with adjustable trip
point and delay is mounted on the front face of the electronics
unit.
The Overfire Air Timer Auxiliary Function is a delayed
de-energization timer that provides relay contacts for the
control of smoke-reduction air in coal-fired installations. As
soon as opacity exceeds the alarm trip point, the relay is
energized. It remains energized as long as the alarm condition
persists. After the alarm condition is corrected, the relay
remains energized for an adjustable period up to five minutes.
Model A-08740 Opacity Monitors equipped with the overfire
air timer function have four LED indicators on the front of the
electronics panel, marked Clear, Smoke, Alarm, and Overfire
Air.
Light Receiver
1
Light Source
Panel Insertion Depth < 6".
Open-mounted A-8740 Opacity Monitor.
2
Dimensions for surface-mount and semi-flush
mount models.
Bulletin A08740.00
3
SPECIFICATIONS
Power requirements:120 V AC ± 10%, 50/60 Hz.
Ambient temperature ranges: 32–130F (0-54C) for electronics unit.
32–160F (0-70C) for light source and receiver units.
Fuse: One, @ 1 amp.
Measurement range: 0 to 100% opacity.
Retransmit Output range: 4–20 ma DC, 750 ohms maximum load.
Directly proportional to measurement range, where 4 ma = 0% and
20 ma = 100%. Output is grounded (not isolated.)
Resolution: Digital meter reads 0–100% opacity with 1% resolution.
Response time: 1 second for 90% of actual change in opacity.
Accuracy: ±5% opacity under all specified operating conditions.
Light source to receiver distance: minimum 4 ft. (1.2 m.), to
maximum 20 ft. (6.0 m.).
Light source lamp life: 1 year minimum.
Spectral response of photocell: 350–1100 nm.
HOW TO ORDER
Cable length: 250 ft. (76 m.) maximum.
The basic catalog number for the Hays Cleveland Model
A-08740 Universal Opacity Monitor is shown below. Replace
suffixes A and B with selections from the table below.
Indicators:
Green: “Clear” LED.
A-08740-*0 -AB
Yellow: “Smoke” LED and flashing display.
(*0 = Current Model).
The standard base unit includes light source and receiver units.
The electronics unit has a vacuum fluorescent display with 3
LED’s (standard: Clear, Smoke, and Alarm) or 4 LED’s (if an
auxiliary function is present). Standard features include:
adjustable alarm trip point and delay, field-selectable auto/
manual alarm reset, a contact closure for a remote alarm
(customer-supplied or quoted separately with Hays Cleveland
L-05500-00), retransmitted 4-20 ma DC output, a serial printer
port (printer not included), and Modbus communication. The
Red: “Alarm” LED and flashing display.
Alarm timer: adjustable 0-300 second delay.
Alarm trip point: adjustable 0-99% opacity.
Alarm reset: automatic. Can be field-configured to manual.
Alarm contacts: isolated SPDT, 10 amp, 120 V AC resistive, failsafe.
Purge delay timer: adjustable 1-600 second delay.
Overfire air timer (optional): maintains contact closure after smoke
abatement for a period adjustable from 1-300 seconds.
Overfire air contacts: isolated SPDT, 10 amp, 120 V AC resistive,
failsafe.
Model A-08740 Universal Opacity Monitor replaces Model A08711.
Housing for enclosed models: NEMA 1.
Relative Humidity: 0-90%, non-condensing.
A: Auxiliary Application Functions
0. None.
1. Burner Cutoff Timer with audible alarm on
front of electronics and “Burner Off” LED.
NYC DEP approved.
2. Overfire Air Timer with “Overfire Air” LED
(for stoker applications).
B: Housing
Are you
0. Open-mounted
reading
a FAX or a
(for OEM applications).
COPY
of
this bulle1. Surface-mount
tin? DOWNLOAD the
(for wall-mounting). NEMA 1.
full-color
PDF version
2. Semi-flush mount
of
this
and
other
(for panel-mounting). NEMA 1.
Printer port: RS232 serial port, DB9-M connector, 9600 baud, N81 (no
parity, 8 data bits, 1 stop bit). Output format: 5 sequence #, blank space,
3 digit opacity, “%” symbol, carriage return, line feed. Output adjustable,
generated every 0–60 minutes, where 0 = disabled.
Example: 01234 011% c/r l/f.
Shipping Weight: varies with options.
Electronics units in enclosures are 7.5 to 8.5 lbs.
Open-mounted electronics units are 6.5 to 8.0 lbs.
Light source and receiver, combined, are 9 lbs.
Approvals: NYC DEP. UL &CUL pending.
Modbus Communication: RTU. 9600 or 19200 Baud rate. N/8/1 (no
parity, 8 databits, 1 stop bit).
Specifications Subject to Change.
Visit us on the World Wide Web at
www.hayscleveland.com
Hays Cleveland Div. of UniControl Inc.
1903 South Congress Avenue
Boynton Beach FL 33426
Telephone: 561.734.9400
Fax: 561.734.8060
email: salescombustion@unicontrolinc.com
literature at our
website!
Hays Cleveland Div. of UniControl Inc.
1111 Brookpark Road
Cleveland OH 44109
Telephone: 216.398.4414
Fax: 216.398.8558
email: salescombustion@unicontrolinc.com
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